It’s miserable on mobile. Confusing unlabeled next button at the bottom of the page, plus an orange next button that seems to do the same thing but sometimes randomly overlaps the content.
I did not test on mobile and maybe it should have all the steps in single page for that aspect ratio (easier to simply scroll). However, for desktop, it was such a beautiful way to guide the reader each step of the way. It was really well done.
Why not have all the content on one page?